The invention relates to an exhaust-gas turbine for a turbocharger of an internal combustion engine, including a turbine casing with a rotor rotatably supported therein, an inlet duct, and a guide vane structure movable into, and out of, an annular space surrounding the rotor, by means of an actuating device.
DE 196 45 388 A1 discloses an exhaust-gas turbine, in which a guide vane structure can be moved axially into an annular space between a spiral inlet duct and a radial rotor. This is done by an axial slide, which is integrally formed with the guide vane structure at one end face thereof and at the same time serves as a cover disc for the guide-vane structure. The axial slide is adjustable axially via a radially extending slide pin which is guided in an axial slot of a turbine casing. At its free end face, the guide-vane structure has a second cover disc which, in a retracted position of the guide-vane structure, in which the guide-vane structure is located in an annular gap between the turbine casing and an inner guide of the guide-vane structure, covers the annular gap and prevents exhaust gases from escaping in an uncontrolled manner via the annular gap. In the extended position, in which the guide-vane structure is located in the annular space, the axial slide closes the annular gap with the exception of a play necessary for adjustment movement.
Furthermore, DE 100 28 751 A1 discloses an exhaust-gas turbine including a guide-vane structure, which is limited axially by two cover discs. One cover disc has integrally formed on it an axial slide, which is guided at its free end in a slot by axially extending slide pins. The sliding pins project through the slot. To adjust the axial slide, a slide sleeve acts on the free end faces of the slide pins. In the retracted position of the guide-vane structure, the cover discs and that region of the axial slide which is adjacent to the inner cover disc close the annular gap. In the extended position, the annular gap is closed, with the exception of the play necessary for adjustment, by the inner cover disc and the adjacent region of the axial slide.
It is the object of the invention to provide an arrangement for the accurate adjustment of the guide-vane structure in a simple manner over the entire adjustment range.